This invention generally relates to a method for assuring enhanced signal integrity in various electronic components operating at higher frequencies. In particular, the present invention relates to a method for optimizing via structures in such components. More particularly, the present invention relates to a method for optimizing via structures for the enhanced high frequency performance of printed circuit boards and backplanes.
Today's electronic products, including computers, cellular telephones, and networking systems operate at ever increasing transmission data rates. At higher transmission data rates, resistance, dielectric absorption, and radiation losses, cross-talk, and structural resonances of passive interconnects can significantly degrade the quality of signals propagating through the interconnect. One of the primary circuit elements that attenuates and distorts analog, radio frequency and digital signals is the via. Via signal degradation is frequency/data rate dependent.
Numerous techniques have been used to mitigate the signal degradation problem including backdrilling of via stubs and removal of non-functional pads. These techniques, however, have seen limited, and to some extent, been subjectively applied in an attempt to improve the signal integrity of complex printed circuit boards and backplanes. It is, therefore, desirable to provide an objective, cost-effective method for the optimization of the shape and size of each via structure within such a printed circuit board or backplane. Additionally, it is desirable to provide such a method that is capable of being applied to other elements of an existing circuitry, such as collections of interconnect components (i.e., backplane assemblies that include vias, traces, and connectors) so as to enhance the circuit's overall signal integrity performance and thus its effectiveness for use at higher operating frequencies.